I have patialy built my house about 60k east of rayong I have formed a large moat arond the 2 acre property and the soil was used to elevate the house about 1.5 meters to aleviate flooding.I wish to farm fish in the moat as it about 14ft wide and 10ft deep the problem I have is that moat will not hold water for any leangth of time hence I will to line it. Could you give some advice on where and approx cost per meter or if you have any alteratives that might work. I will post photos later

If it is a large area, best to use clay, you will have to drain it and buy it buy the truckload and have it placed by an excavator to do the best job. Make sure clay and all clay and not the crap black stuff or red stuff, must be clay clay and all clay.

i think nawty hit the nail on the head with the clay that sort of size area even clay lining it will cost a fair sum am i understanding it you have surrounded the whole plot with this moat do you have any water in it at all if so have you studied the rise and fall over the course of a year to locate your water table height

my comments may be wrong but never deliberatelyIf it aint broke, dont fix it

Turtle......clay lining is how almost all dams in country Thailand and Oz and almost anywhere are made to hold water.

Also as questioned by Geordie, your moat may become a cracked clay wastepan in the dry if you do not have a high enough water table or an adequate way of topping it up......nothing worse than green sludge at the bottom of your moat....will not keep the crusaders out.

you have an oportunity there the dutch used water wheels to drive pumps to drain land have you enough flow to reverse it block the spring off from the moat and use the waterflow to pump water from the sping into it it sound daft but it could work depends on the flow rate of the spring against the leak rate of the moat alternately dump a load of clay in the area of the spring fill up and see if that is the only problem areadoes the spring have water feeding through it as well as what you put in there

my comments may be wrong but never deliberatelyIf it aint broke, dont fix it

Dozer I will try as you suggest but as the water table rises it may push through the clay and dispures it other than that I might have to back fill 8 or 10 ft back with clay.PS did you recieve the photo's

Hi tutle2: I didn't suggest anything, must have been someone else. I did get some photos you sent..... can you upload them to this thread, so everyone can see them? Just click on the Upload attachment and go from there.....

A Thai architect friend visited me up here the other day, got talking about ponds and 4 years ago a friend of his built a pond and wanted my friends help to make sure it was what he wanted.

First, he had no natural water suppll to fill it, so they sunk a bore.

Secondly, the pond was 10m deep and about 100m x 30m...so not tiny.

He wanted it lined to keep water in and keep it clear. So they dug a shelf around the edge, about half a metre below the surface/edge, then lined the hole pond with the simple black pvc plastic and the company that supplied it, welded it altogether.

It sat just on the edge of the shelf and then the last little bit between the edge of the shelf and the grassed area was soil, so they could grow plants around the edge up to the drop off.

4 years later and it does not leak, it is clear water and he simply tops it up from the bore, not sure how often this is done, but did not sound excessive.

The total cost for the liner was 15,000b he said.

I would be very willing to do this for my planned pond, but use a heavier gauge plastic, for additional cost.....but i am worried about the water table here being high and rising up under the plastic.

Nawty wrote:....but i am worried about the water table here being high and rising up under the plastic.

If you have water in the pond on top of the plastic it won't allow the ground water to rise up.I had a pvc-lined (concrete in-ground) swimming pool and while it was filled no problems, but when the water level went down by half, the ground water started to get in under the plastic.Filling the pool pushed the ground-water back out. (The water table was about 40 centimetres lower than the top of the pool.)

nawty you could use the dirt you are digging out too build up above the water table and flood level sort of an above ground pool unlike most members you have the water to fill it fredik is right about the importance of keeping the pond water higher than the water tableto keep the liner in place seems cheap for a project that size

my comments may be wrong but never deliberatelyIf it aint broke, dont fix it

Not sure about this but am thinking of trying it as insurance against high water table events/gas build up when I install plastic lined ponds: slope the pond bottom to a low point & install a swimming pool type hydrostatic valve into a gravel well.I don`t want to raise my pond edges above the grade ( aiming for the natural look). This company have very reasonable pvc/ldpe prices & have been helpful answering questions: http://www.scv-plastic.com/slan.html